The ImageGear TWAIN component exposes the following enumerations:

enumIGTWAINAlarms	Determines specific audible alarms.
enumIGTWAINAudioFormats	Determines which Audio file formats are supported.
enumIGTWAINBarcodeRotation	Determines the bar code's orientation on the scanned image.
enumIGTWAINBarcodeSearchModes	Restricts barcode searching to certain orientations
enumIGTWAINBarcodeType	Determines the type of bar code found on a page.
enumIGTWAINBitDepthReduction	Specifies the Reduction Method the Source should use to reduce the bit depth of the data.
enumIGTWAINBitOrder	Specifies how the bytes in an image are filled by the Source.
enumIGTWAINCBType	This enumeration determines the type of callback function.
enumIGTWAINClearBuffers	Determines the type of buffer clearing process.
enumIGTWAINColorDataFormats	Allows the application and Source to identify which color data formats are available.
enumIGTWAINContainerType	Capability container type.
enumIGTWAINControlParams	TWAIN control parameters.
enumIGTWAINCountries	Specifies the country originated the scanned document.
enumIGTWAINDeskewStatus	Determines the status of the deskew operation.
enumIGTWAINDeviceEvents	Determines the device event.
enumIGTWAINDuplex	Determines whether the scanner supports duplex.
enumIGTWAINFeederAlignment	Determines which special actions application may need to take when negotiating frames with the Source.
enumIGTWAINFeederOrder	Determines the order of scanning.
enumIGTWAINFileSystem	This enumeration determines the configuration of TWAIN file system.
enumIGTWAINFileType	File types in the device's file system.
enumIGTWAINFilterType	Determines the color characteristic of the subtractive filter applied to the image data.
enumIGTWAINFlashUsed	Determines which flash the image was acquired to use.
enumIGTWAINFlipRotation	Determines the orientation of images that flip orientation of every other image.
enumIGTWAINImageFilter	Determines the algorithm used to improve the quality of the image.
enumIGTWAINJobControl	Determines how the job can be processed,
enumIGTWAINJPEGQuality	Specifies the kind of JPEG quantization tables that tradeoff quality versus compressed image size.
enumIGTWAINLanguages	Specifies language of the scanned document.
enumIGTWAINLigthPath	Determines whether the image is captured transmissively or reflectively.
enumIGTWAINLightSource	Determines the general color characteristic of the light source used to acquire the image.
enumIGTWAINMessages	This enumeration represents capability control messages.
enumIGTWAINNoiseFilter	Selects the algorithm used to remove noise.
enumIGTWAINOrientation	Determines which edge of the "paper" the image's "top" is aligned with.
enumIGTWAINOverscanModes	Determines the over-scanning mode.
enumIGTWAINPatchCode	Determines prioritized list of patch code types dictating the order in which patch codes will be sought
enumIGTWAINPixelFlavor	Describes the sense of the pixel whose numeric value is zero (minimum data value).
enumIGTWAINPixelType	Specifies the type of pixel data that a Source is capable of acquiring (for example, black and white, gray, RGB, etc.).
enumIGTWAINPowerSupply	Reports the kinds of power available to the device.
enumIGTWAINPrinter	Determines the printer devices being used by application.
enumIGTWAINPrinterModes	Specifies current printer mode.
enumIGTWAINSupportedSizes	Specifies the size(s) the Source can/should use to acquire image data.
enumIGTWAINUnits	Determines the unit of measure for all quantities.
enumIGTWAINXferFlags	This enumeration provides the flags for transfer mechanism.
enumIGTWAINXferType	Determines which type of transfer mechanisms the application and Source have in common.